Method of forming sand molds.



No. 836,342. I PATENTED NOV. 20, 1906.

J. A. RATHBONE.

METHOD OF FORMING SAND MOLDS.

APPLICATION FILED MAR. 5, 1906.

[ lia] V H53.

JOHN A. RATHBONE, or uric-A, NEW YORK.

METHOD OF eonmme SAND MOLDS.

Specification of Letters Patent Patented Nov, 20, 1906.

Application filed March 1906. Serial No. 304.387-

.lo all whom it may concern.-

Be it known that I, JOHN A. RATHBONE, a citizen of the U nit-ed States of America, residing at I tica, in the county of Oneida and State of New York, have invented certain new and useful Improvements in Methods of "tionary sand-holder; but in either case'the Forming Sand Molds, of which the following is a specification, reference being had therein to the-accompanying drawings.

.In the present state of the art it is almost universal practice in the formation of sand molds to fill the loose sand into the flask upon an up-facing pattern and then to compact the sand either by tamping or by pressure. The advantage of this method is that the interstices of the pattern are filled with sand by gravity, while the impact of the sand against the pattern face causes a certain degree of compression.

imprint of the pattern is thus initially formed As "a consequence a perfect and the subsequent tamping or pressure will impart the )roper degree of hardness to all portions of tile molding-face.

In multiple molding, where it is necessary to form molding-faces upon opposite sides of the flask, the lower face only can be formed by this method. It has therefore been found impracticable to form a good imprint of the pattern upon the up or face ofthe sand and for the reason that t e movement of the pattern downward into the sand will cause the projecting portions to carry the sand'awayfrom the cc of the depressions or interstices of the pattern, leaving soft spots in the molding-face, which will not retain the proper shape. Thus gravity, which assists 1n the formation of the molding-face against the upturned attern, has precisely the op ositeeffeet in 516 formation of the face by t e down turned pattern. I

With the present invention difiiculty of forming an imprint of the down turned pattern is overcome by increasing the yelocity of movement of the said pattern relative to the body of loose sand-to such an extent as to (practically eliminate gravity as a factor an to compact the sand against the patternfaceby inertia. This may be accomplished either by moving ,the sand-holder upward in relation'to a stationary attern or by movthe pattern downwar in relation to a staessential factor is the requisite velocity of the moving part.

In carrying out my improved method I preferably employ a ,niolding-machinesuch as illustrated in the drawings, in which Figure 1 is a vertical section through the mold-flask and opposed patterns before the operation of compacting the sand. Fig. is a-similar View after the compacting operation.

Fig. 3 is,a section through. a portion of the mold, illustratingin dotted lines the defect overcome by the invention.

A is a mold-flask, B an upturned pattern, and C the opposed or downturned pattern.

These patterns are mounted upon relatively.

movable members of a molding-machine of any suitable construction which is capable of im arting the required velocity to the move le member. As shown, the pattern B issecured to lower head D, upon which the flask A is also carried, and this head is secured to a plunger E, moved upward by any suitable means. face pattern 0 is secured to a stationary upper head F.

G is a sand-frame or othersuitable means for retaining the proper quantity of loose sand-to fill the mold-flask when compacted between the opposed pattern-faces.

In operation, the flaskA being placed upon the head D, loose sand is filled therein and into the sand-frame G thereabove and is struck ofl flush with the top of the latter.

(Notshown) The down- Motion is then imparted to the plunger E, which carries upward the head D, pattern. B,

flask A,'and sand-frame G, and by the time the upper pattern C contacts with the sandthe parts are moving at a high velocity. Inertia will thus cause the sand to enter all the interstices of the downturned pattern and to strike against the face thereof with sufficient impact to form a perfect imprint. This formation of the molding-face occurs in advance of the completion. of movement of the head D, so that during the final movement the body of sand between the molding-faces What I claim as my invention is- 1. The method of forming sand molds which consists in relatively moving toward each other a body of sand and a down-facing superposed pattern, with suflicient velocity to compact the sand against the pattern-face by inertia. "t

2. The method of forming sand mol'ds which consists in filling a holder with loose sand, superposing a down-facing pattern in relation thereto and imparting a relative movement ofsuflicient velocity to compact the sand against the pattern-face by inertia.

3. The method of forming sand molds which consists in filling a mold-flask with sand upon an upfacing pattern, superposing a down-facing pattern in relation thereto and relatively moving said patterns with sul Ii cient velocity to compact the sand against the up per pattern-face by inertia.

4. The method of forming sand molds which consists in relatively moving a body of sand and an opposed pattern-face, with sufli .ity to compact the sand against the face of the pattern by the inertia of the sand, unas "sisted by gravitvL 6. The method of forming sand molds which consists in imprinting a pattern in a body of sand by relatively moving said pattern and body of sand with sufficient velocity to compact the sand against the pattern-face by the inertia of the sand, acting contrary to gravity.

In testimony whereof'I a'HiX my signature in presence of two witnesses.

JOHN A. RATHBONE.

Witnesses:

JAMES P. BARRY, AMELIA WILLIAMS. 

